Hi
Thank you for raising the question.
Did the ITSM connector worked before or is it a new one?
Did you try to check the errors in the Dashboard (https://learn.microsoft.com/en-us/azure/azure-monitor/alerts/itsmc-dashboard).
Did you try to sync your connector? https://learn.microsoft.com/en-us/azure/azure-monitor/alerts/itsmc-resync-servicenow
Hope that this helps you in order to start your investigation.